I need help please..disturbing but..

I feel like there is something wrong with me I have such a hard time orgasming when I have sex what if I  have a sexual disfunction because half the time I can't orgasm...only one position works with my husband and I..I'm terrified to tell him that I don't usually orgasm but I might wreck him if I tell him..he's great in bed it just takes so much for me..so lost :/